Loom shedding mechanism

ABSTRACT

A heald shaft operating means for a heald shaft of a loom whereby the shaft is operably associated with a pivotal lever arranged to be driven in one directional sense by the action of a cooperating cam means acting upon a follower carried by the lever, and in the opposed directional sense by the action of a compression spring operably associated with the pivotal lever.

United States Patent Griffith Aug. 14, 1973 [54] LOOM SHEDDING MECHANISM2,510,404 6/1950 Lake et a] 1. 9/82 3,230,983 l/l966 E 139/82 [75]Invent g g a Lmlewe" 2,263,678 11/1941 c s rnan 139/79 er y, ng an OTHERPUBLICATIONS [73] Assignee: Bonas Machine Company Limited,

Staffordshire Great Britain 2gO9247,g55 12-1970 German Application(Menegatto) [22] Filed: Feb. 29, 1972 [21] Appl. NOJ 230,319 PrimaryExaminer-James Kee Chi Attorney--James E. Nilles [52] US. Cl. 139/79,139/57 57 ABSTRACT [51] Int. Cl D03d 5/00 1 [58] Field of Search 139/79,78, 82, 88, A heal! Shaft Pemm8 means heald Shaft of a 89/57 55 32 80loom whereby the shaft is operably associated with a pivotal leverarranged to be driven in one directional 56] References Cited sense bythe action of a cooperating cam means acting upon a follower carried bythe lever, and in the op- UNITED STATES PATENTS posed directional senseby the action of a compression gieneglzlitto 139/78 Spring operablyassociated with the pivotal level: i y laZZO a 3,l86,440 6/1965 League139/88 4 Claims, 3 Drawing Figures Patented Aug. 14, 1973 2 Sheets-Sheet1 Patented Aug. 14, 1973 3,752,194

2 Sheets-Sheet 2 LOOM SHEDDING MECHANISM This invention concernsnarrow-fabric weaving looms, and in particular, though not exclusively,a shedding mechanism for such looms.

It is known in some loom constructions for heald shafts to be operatedby levers which are held each in contact with the surface of aco-operating cam by means of tension springs located at or near to theextremity of the lever to which the heald shaft is connected. Such anarrangement, whilst being effective, has the disadvantage that thepositioning of the spring is such that, in use its amplitude of movementwill be relatively large and thus the springs to have a long operativelife must be of sturdy construction, and thus comparatively heavy formand this leads to the creation of high inertia forces which tend tolimit the speed of operation of the loom to a value lower than thatwhich, in narrow fabric looms in particular, is desirable.

It is the object of the present invention to provide a sheddingmechanism which will overcome or at least substantially mitigate theabove outlined disadvantages and thus enable the loom to operate at thevery high speed demanded by the present-day looms.

According to the present invention there is provided a loom sheddingmechanism characterised in that the heald shaft is operably associatedwith a pivotal lever arranged to be driven in one directional sense bythe action of a co-operating cam means acting upon a follower carried bythe lever, and in the opposed directional sense by the action of acompression spring operably associated with the pivotal lever.

The invention will now be described further, by way of example only,with reference to the drawings accompanying the ProvisionalSpecification, in which:

FIG. 1 is a schematic side elevation of a loom including a sheddingmechanism according to one form of the invention.

FIG. 2 is a detail view on a larger scale of a second form of a loomshedding mechanism, and

FIG. 3 illustrates diagrammatically a heald frame and its manner ofmounting in a loom.

Whilst the drawings and following description relate to a narrow fabricloom it is to be understood that the shedding mechanism may be appliedto a loom of the kind used for weaving broad fabrics.

As shown in the drawings and in particular FIG. 3 there is provided aheald frame 10 whose vertically disposed elements 10a are constrainedlaterally by short guide blocks 13 mounted on slide elements 18 whichguide the frame in its vertical movement. The slide elements 18 aremounted on the loom frame 14. The guide blocks 13 are, as shown locatedbetween upper and lower heald bars 15 and thus must be short enough toallow for unrestricted vertical movement of the heald frame 10 betweenupper and lower shed positions. A connecting rod 12 is rigidly attachedat its upper end to heald frame 10 and pivotally connected in thetransverse plane at its lower end to the extremity 16 of one arm 17 of apivotal lever 17a. The connecting rod 12 has sufficient inherentflexibility to accommodate for the arcuate displacement of the leverextremity 16 when the loom is in use. The pivotal lever 17a has as itsfulcrum a pivot shaft 11 and extending from this fulcrum in a directionopposite to arm 17 is a short arm 17b provided at its end with a camfollower 19 in the form of, for example a roller. The follower member 19is caused as shown in FIG. 2, to make contact with the surface of aco-operating cam 20 mounted on a camshaft 21 journalled in the loomframe 14 and driven at an appropriate speed from the loom main shaft(not shown). The contact of follower 19 with cam 20 is maintained by useof a compression spring 22 acting on the arm 17 of pivotal lever 17a atclose proximity to pivot shaft 11 (that is at a distance from the pivotshaft 11 no greater than the distance of the axis of the cam follower 19from the pivot .shaft 11). Compression spring 22 is guided and providedwith a re-action face by sheath block 24 mounted on the loom frame 14. Aslidable piston 25 abuts the free end of the compression spring 22 andis provided with a push rod 26 having spherical formed ends 260 whichare seated in mating spherical depressions 27 formed in both the piston25 and the arm 17. Because of the close positioning of the cam followerl9 and compression spring 22 to the pivot shaft 11 the moment of inertiaof the pivotal lever 17a about its fulcrum will thereby be kept to a lowvalue, as will the bending moment which will be induced upon the arm 17of the pivotal lever 17a only by the load derived from moving the healdframe mass and not by the force of the compression spring 21 and hencethe proportions and thus the mass of this arm 17 can advantageously besomewhat less than is the case in known looms. Furthermore, theoscillations of the compression spring 22 will be of small amplitude dueto the proximity of the spring to the fulcrum of lever 17a as will bethe movement of the piston 25 and push rod 26 thereby keeping to a lowvalue the inertia force deriving from these components and thus enablingvery high operating speeds to be achieved.

As indicated in FIG. 1 the cam 20 may be replaced by a chain 28 thelinks of which are so formed as to produce a cam surface so that largepattern repeats can be achieved.

The invention is not restricted to the details set out above. Forexample, the dispostion of the follower l9 and spring 22 relative to thepivot shaft 11 can be altered to give the same effect; Details of suchmodifications will suggest themselves to persons skilled in the art ofloom construction and thus it is not thought to be necessary to setthese out in detail in this specification.

I claim:

1. A loom shedding mechanism comprising; a heald shaft; a lever pivotalabout a fulcrum and operatively associated with said heald shaft; afollower carried by said lever; cam means cooperating with and actingupon said follower for driving said lever in one directional sense; acompression spring operatively associated with said lever for actingupon said lever in an opposed directional sense; the said follower andthe said compression spring being positioned on opposite sides of saidfulcrum with the compression spring in close proximity to the saidfulcrum and a piston and push-rod assembly by means of which saidcompression spring acts upon said pivotal lever.

2. A loom shedding mechanism according to claim 1 including a cylinderin which said compression spring and said piston are mounted, said pushrod extending between said piston and said lever.

3. A loom shedding mechanism as claimed in claim 1 in which the push rodis provided with partly spherical ends seated respectively incorresponding receiving formations in said piston and. said. lever.

that said heald frame is retained between said guide means throughoutits entire range of movement; and guide blocks mounted upon said healdframe guide means between said spaced heald receiving bars forconstraining said heald frame from lateral movement. i i IF

1. A loom shedding mechanism comprising; a heald shaft; a lever pivotalabout a fulcrum and operatively associated with said heald shaft; afollower carried by said lever; cam means cooperating with and actingupon said follower for driving said lever in one directional sense; acompression spring operatively associated with said lever for actingupon said lever in an opposed directional sense; the said follower andthe said compression spring being positioned on opposite sides of saidfulcrum with the compression spring in close proximity to the saidfulcrum and a piston and push-rod assembly by means of which saidcompression spring acts upon said pivotal lever.
 2. A loom sheddingmechanism according to claim 1 including a cylinder in which saidcompression spring and said piston are mounted, said push rod extendingbetween said piston and said lever.
 3. A loom shedding mechanism asclaimed in claim 1 in which the push rod is provided with partlyspherical ends seated respectively in corresponding receiving formationsin said piston and said lever.
 4. A loom shedding mechanism according toclaim 1 wherein said heald shaft comprises: a movable heald frame havingspaced heald receiving bars; a connecting rod connected to said leverand to said heald frame; a heald frame guide means to constrain saidheald frame in a fore and aft direction and being of such dimensionsthat said heald frame is retained between said guide means throughoutits entire range of movement; and guide blocks mounted upon said healdframe guide means between said spaced heald receiving bars forconstraining said heald frame from lateral movement.